Results from studies of language identification in noise and of word identification from tachistoscopic presentation clearly indicate that contextual information can be used to facilitate word identification under inadequate stimulus conditions. But these results do not provide strong evidence that such an interaction is occurring during normal reading. Other forms of evidence using tasks more similar to reading (proofreading errors and errors in reading aloud) produce the same dilemma. Three aspects of perception have been identified that might be affected by contextual information: where the eyes are sent, the visual region attended to, and the visual information within that region that is used for reading. But studies that have investigated perception during reading are not definitive on these issues; and there currently appears to be no clear evidence that the contextual information environment exerts control over what visual information is used in reading, that is, over the functional stimulus. In fact, subjects appear to be responding to considerable visual detail of words that are almost completely constrained by their prior context. From present evidence, then, it seems quite possible that contextual facilitation is not achieved by reducing the amount of visual information a reader acquires from individual words. (RL)